1. Field of the Invention
The present invention relates to a complex and an application thereof and, more particularly, to an iron complex, a manufacturing method thereof, and an iron oxide catalyst constructed thereby.
2. Description of the Related Art
Catalysts are usually used to catalyze oxidation-reduction reaction. Currently, in petrochemistry and energy industry, noble metals such as Platinum (Pt) are still considered as a main source of catalysts. In petrochemistry industry, Pt catalysts are used to increase amount of petroleum. Moreover, in most of gas-cleaning facilities of vehicles, Pt catalysts are used to transfer carbon monoxide (CO) and hydrocarbon into harmless carbon dioxide and water. In energy industry, the developing fuel cell for commercial purpose is attracting more attention because a fuel cell has many advantages such as high efficiency and low emission; moreover, a fuel cell only emits harmless carbon dioxide, water and air. Therefore, the fuel cell can be a substitute for green energy wherein a great quantity of Pt or Pt on carbon-supported catalysts is applied on most of fuel cells to promote oxidation-reduction reaction wherein.
However, in the short term, using Pt catalysts or Pt on carbon support catalysts for fuel cell is practicable, but in the long term, non-noble metal catalysts must be considered as alternative catalysts for reducing manufacturing cost. If non-noble metal catalysts can be used as alternative catalysts of noble metal such as Pt catalysts or Pt on carbon-supported catalysts, the usage of catalysts can be widen. For example, manufacturing cost for membrane electrode assembly (MEA) in proton exchange membrane fuel cell (PEMFC) cannot be reduced due to the expensive cost of noble Pt catalysts used in fuel cell.
Several types of non-noble catalysts have been explored in recent years, including transition metal alloys, metal nitrides, and chalcogenides. For replacing noble catalysts by non-noble catalysts, the development of non-noble catalysts such as heat-treated Fe— and Co—N/C catalysts has led to progress in catalyst synthesis methodologies to lower manufacturing cost in fuel cell.
A conventional manufacturing method of Fe—N/C is shown in Electrochimica Acta. Vol. 42 No. 9, pp. 1379-1388, 1997 entitled “Is nitrogen important in the formulation of Fe-based catalysts for oxygen reduction in solid polymer fuel cells?.” In this conventional method, 150 mg of Ferrocene, Fe(C5H5)2, is dissolved in benzene acting as a solvent. Then, 2 gs of carbon black (XC-72) are added to the solvent and stirred to get a solution. Following, the solution is heated in order to distill the solvent to obtain an iron mixture. The iron mixture is dried at 75° C. in air to get a dried iron mixture wherein Fe loading is 2 wt %. Then, the dried iron mixture is ground before being loaded into a quartz basket while the ground iron mixture is introduced with Ar in a quartz tube at room temperature for 30 mins. The quartz tube is then placed in a split furnace preheated to 1000° C. and acetonitrile (CH3CN) vapor is introduced into the quartz tube by bubbling Ar in acetonitrile maintained at room temperature. The dried iron mixture is pyrolyzed for 2 hours. The quartz tube is removed from the split furnace and cooled to room temperature before stopping the Ar gas flow so that Fe—N/C catalysts can be obtained.
In sum, the conventional manufacturing method of Fe—N/C is to reduce particle sizes of the dried iron mixture by grinding at first. Then, during pyrolysis period, acetonitrile (CH3CN) vapor is introduced into the quartz tube to let Fe ions in the dried iron mixture and N ions in the acetonitrile bond together to form Fe—N/C catalysts. Therefore, the conventional manufacturing method of Fe—N/C cannot precisely control the particle size, uniformity, and dispersion of the dried iron mixture constructed the catalysts, so that surface area of the catalysts and the ability of catalysis cannot be increased. As a result, the above introduced Fe—N/C catalysts cannot actually replace the noble metal catalysts in use. Besides, the benzene solvent and acetonitrile used in the conventional manufacturing method of Fe—N/C are toxic materials resulting in harmful effect to the environment. Hence, there is a need to provide an iron complex, a manufacturing method thereof, and an iron oxide catalyst constructed thereby.